Birmingham boss Steve Bruce felt Sunderland's late leveller should not have stood due to a foul on keeper Colin Doyle.
With Doyle on the floor, Stern John was on hand to head home from close range to snatch a late 2-2 draw.
"Well I'm thinking to myself 'Where's the keeper?'" Bruce stated after the contest.
"I think everyone knows what O'Donovan's done. Held him and impeded him.
"We thought we were harshly done by. The linesman has to see the player on my keeper."
Bruce is pleased with his side's opening two displays, but feels they need to cut out their naive mistakes.
"We've put in two decent performances, but we've been punished and this is what the Premier League is about," he continued.
"We've switched off here, given a free-kick away. Overall, I'm disappointed because it feels like a loss when you concede in the last minute."